The present invention relates to a one-piece golf ball or a golf ball having a core and a cover of one layer or a plurality of layers. More particularly, the invention relates to a golf ball which is suitable for use as a practice golf ball.
Because sufficient durability cannot be achieved when zinc methacrylate is used in a rubber composition for practice golf ball cores, JP-A 2012-228452 discloses compounding that uses methacrylic acid instead. However, methacrylic acid, as an acid, has the power to corrode metal, making it essential to design the manufacturing facility to acidproof specifications and thus necessitating, in this and other ways, capital investments. Also, worker safety must be taken into account in the manufacturing processes, all of which is very burdensome for production.
JP-A H10-85367 discloses art that holds down the decrease in core resilience by minimizing the moisture present in golf ball rubber compositions.
Conversely, JP-A 2002-102388 describes the addition of moistened rubber powder to a rubber composition as one way to inexpensively lower the resilience of practice golf balls.
The above prior art discusses methods for lowering rebound and techniques for maintaining a high durability. However, no mention whatsoever is made in this prior art of being able to lower the burden on production facilities and ensure good productivity.